iThemes Security Pro v5.9.4 is the best WordPress security plugin that works to fix common WordPress security issues you may not know exist. By adding an extra layer of protection, iThemes Security Pro helps give you peace of mind and keeps the bad guys out. With WordPress two-factor authentication, users are required to enter both a password and a secondary code sent to a mobile device such as a smartphone or tablet. if you want you can also able to download previous version of this plugin iThemes Security Pro v5.9.0.